Friday, 29 April 2011
I had to go on the cnc machine in Fás today. A part I made earlier had a circle missing from the middle of it. There is a photo of the (now incomplete) part in the blog post "computer-aided manufacture". One of my colleagues on the course pointed out that it was missing. I checked the drawing on the alphacam and, sure enough, it was in the drawing but I forgot to put a machining operation on it so it never came out in the program. It was easily fixed on the cam, but the machining aspect was a bit finnicky. After setting the only tool needed, I put the part in the vice and zeroed it using the probe. I ran the program from the tool change line for the work I wanted doing. So it machined the circular pocket perfectly and went on to clean the corners of the square pocket that the 4 holes are in. But this left a bit of roughness and a burr on the bottom of the square pocket so I had to go into the cam, do another pocket cycle and run it again. So most of the day today was taken up with correcting one small toolpath omission from alphacam. But it was good practice in case I come across changes to parts in my future work with Schivo Group. I am starting in their Waterford facility on the 9th of May.
Thursday, 21 April 2011
On the Machine again today. A lot more machining and some practical and theory tests before my course finishes. But not enough time because I'm expected to start a new job soon. Worse again is the fact that I'm off 'til Wednesday and then another bank holiday the following week. So I don't know how I'll cram all that's needed to earn my certs in such a short space of time. Some of those that hadn't a clue should not have come on the course in the first place. It's their getting bogged down that's slowing the rest of us. Anyway, I'll keep flat out with the machining and necessary paperwork until I'm due to start my new job. Hopefully there will be an aptitude clause somewhere in the conditions for earning the cert. I hope to get a go at the big Mori Seiki machine next week. I was told I'd at least get another chance to observe and learn. I have a program ready if I get to set up the tools and run it. Tweaked the lathe program as well today and that's ready to run also. Anyway, the part in the photo is called "Machine Cover". It's just a CNC milling exercise, it's the type of machining you would do for that type of component. It was fairly straight forward. Just 4 tools. The tricky part was facing the excess material off the bottom. I had to go back to the computer twice to adjust the toolpath in the CAD/CAM to get it right. But the alphacam is so much quicker than editing the program at the machine. It was an enjoyable project though because it kept my mind active.
Wednesday, 20 April 2011
This is the latest part machined on the Bridgeport CNC milling machine. It was programmed using Alphacam. The drawing is converted to Heidenhain programming language for the machine (as opposed to I.S.O. G-codes) and there is usually a minor edit or two at the machine before machining starts. There is a 30 degree countersink in the 4 holes inside in the square pocket. The curved slot is 8mm wide but machined using a 7mm slot drill and a pocket function from alphacam. It was an interesting exercise for the different shapes that needed to me worked on the part. I'm back on the mill tomorrow, although I also have the next lathe part programmed. The next lathe part has 2 internal diameters bored out to 28.5mm and 40mm with an M30 internal thread that has a pitch of 1.5mm. So there's a bit of machining to do... Which I like!
Tuesday, 12 April 2011
On the Lathe today. Essentially these are the same part with different threads. It was a threading exercise. The thread is M36 with a pitch of 2. The 1st on the left has a right-hand thread, the middle one has a left-hand thread and the one on the right has a double start right-hand thread. They are 3 modifications of the same program. The right hand thread was done using a conventional threading cycle. The left hand one was achieved using the same cycle but adjusting the Z axis co-ordinates so that the threading tool runs in the opposite direction. The double start was achieved by doubling the pitch and doing 2 runs - the 1st from Z4 and the 2nd run from Z2. It was a very interesting project. Later we're supposed to be doing a part with internal threads that screw on to these. Hopefully I'll get to mill some of my remaining CAM programs next though. I've 3 programs ready to run on the CNC milling machines.
Friday, 8 April 2011
I went to the banklink to get dinner money before FAS the other day. Coming out from the city centre, turn right at the roundabout at the entrance of Raheen Industrial Estate. There's an A.I.B. and a Centra on the left behind the hotel down that road. There's a clothing bank behind them in the car park. So if I've to get rid of any old clothes while I'm still in Limerick, I'll know where to go.
Tuesday, 5 April 2011
I was machining all day today. First I had to run the part I was milling since yesterday. Had to adjust the tooling and edit a very finicky program but got it eventually. I then had to go to the CNC lathe to machine the part in the photo. Everything went fine until the M20 thread at the end. I didn't know anything was wrong with my program until I heard a bang. I had an R0.5 in the G76 threading cycle. This told the machine to do a 0.5mm finish pass, which turned out to be too much for the tool tip and it broke. I compared my program with a colleague's and the finish pass should have been 0.05mm. After the tool insert was changed, the corrected program ran smoothly. I learned from the mistake.
Monday, 4 April 2011
Was on the Bridgeport CNC today. Made a mistake with the program. Had most of the part run when I spotted the mistake. Decided to correct it in the NC editor and this lead to me making a mistake that made one tool go too deep and ruined the part. So I took it into the computer and had the mistake rectified in the CAD/CAM in less than 5 minutes. I transferred the tool offsets from the original program to the corrected one so that I wouldn't have to set the machine all over again. I'll run the part tomorrow morning, 1st thing. It's a part that I ran before but programmed on the CAD/CAM this time so it's in Heidenhain rather than G-codes. If you look at previous blogs you'll find a square part with 10 holes tapped M6 x 1.0. I used the same program number as last time too, since it's the same part - P110. That's the part I'm running again. I'll be doing new parts as well as part of my CAM training. Plus further CNC lathe work as well.